The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Variable displacement engines provide improved fuel economy and desired torque on demand using cylinder deactivation. When high output torque is required, all cylinders of a variable displacement engine are supplied with fuel and air (i.e., a full-cylinder mode). At low engine speeds, low load, and/or other inefficient conditions, some of the cylinders (for example only, half of the cylinders) may be deactivated to reduce throttle losses and improve fuel economy (i.e., a deactivated mode). The engine may be transitioned from the deactivated mode to the full-cylinder mode when a driver depresses an accelerator pedal to request a torque greater than that can be achieved in the deactivated mode, thereby requiring all cylinders to be active.